I got a used LG incubator (the styrofoam kind with a fan in it and the metal wire around the top that heats up) a few months ago, and I have had very bad luck with hatches in it. Every time I use it, I clean and disinfect it thoroughly with bleach water, then rinse until the bleach smell is gone and let it sit a few days to dry out, to be sure there is no extra water or bleach left in the styrofoam. I have tried several thermometers/humidity gauges in it to be sure I don't have a bad one. All of the thermometers I try read exactly the right temperature in the incubator, 99.5 degrees. The humidity, I have some problems with. If I just fill the tray meant for water in there, the humidity will be good for a few hours, then will crash down to nothing. (I live in the desert and it is very, very dry here, the air sucks the water out of anything!) Or, I can line the bottom with sponges soaked in water, and the humidity will be more stable, but very high...80-90% I can't seem to get in that good range, it's either 20% or over 80% or wildly fluctuating in between. So, would it be better to stay too low, too high, or let it change a lot? I obviously cannot check the humidity every half an hour to adjust it over the whole incubation, that is way too much work! I turn the eggs three times daily, as is normal. (by hand, I don't have an automatic turner) When I open eggs from my hens for eating, they are all fertile. As I would expect, because right now I have an overload of roosters, about as many as I have laying hens. But, on candling, about half my eggs will be clear after a week or two in the incubator--no development at all. Then, I have another small die-off around 4-8 days, they will start to develop then quit. Then another few will quit around 2 weeks. Then when they get to lockdown, half will look good but never hatch, and upon opening I find a perfect but dead chick. The last few hatches I have tried, some started zipping, then died suddenly, like they just ran out of energy. Out of 50 eggs, I will get 1-4 chicks! Obviously something is not right. Is this just because of my humidity issues, or is there something else going on?